Electronic device packages are positioned on and secured to circuit boards in various ways to produce circuit board assemblies. Conventionally, leads extending from the device package are inserted into holes in the circuit board and soldered to circuit patterns on the undersurface of the board by wave soldering or the like. In surface-mount assemblies, the leads are positioned on attachment pads on the top surface of the board and soldered thereto.
To conserve costs, it is preferable to position the device packages on the board by robotic techniques. However, where robotics are used, accurate pre-alignment of the leads with the holes or mounting pads must be assured.
In many applications, density of components on the circuit board is a major consideration. Accordingly, elongated packages are mounted vertically when practical to conserve surface area. Unfortunately, many elongated packages (such as the TO-220 package and similar packages) are not symmetrical or evenly balanced. Thus they tend to tilt from the vertical position before or during the soldering process unless restrained.